What causes a bearing isolator to leak lubricant?
Though true for contact seals, the presence of leaking oil from a Bearing Isolator is most likely due to factors other than seal failure. Following are some of the more common causes of Bearing Isolator lubricant leakage in process pumps.
Why is oil leaking from my bearing housing?
One of the most common field complaints I hear is that the lube oil is leaking out of the bearing housing. The following general checklist will help users find and troubleshoot potential reasons for oil leakage (oil egress) from the bearing isolator in the field.
What causes a bearing housing seal to fail?
This increases mean time between repair (MTBR). The most common perception of bearing housing seal failure on process pumps is lubricating oil leaking from the bearing housing. For most operators, the analysis is simple: no leaking oil means the seal is fine while leaking oil equates to failure.
What should the oil level be in a bearing housing?
Proper oil level is between one-quarter and one-half of the lowest ball in the bearing housing. There are no advantages to a higher oil level. (Courtesy of the author) ❑ The bearing housing is overfilled (oil overfill). This is the most common problem I witness. The oil level should be maintained at the middle of the sight glass and no higher.
What causes an oil leak from a bearing isolator?
Excessive vibration could be caused by cavitation, air binding, imbalance, surging, improper operational area and/or misalignment of the driver. Note that vibration is not a likely cause of oil leakage because the bearings and seals will normally fail first. ❑ Occasionally the oil leaks out, but not because of the bearing isolator.
Proper oil level is between one-quarter and one-half of the lowest ball in the bearing housing. There are no advantages to a higher oil level. (Courtesy of the author) ❑ The bearing housing is overfilled (oil overfill). This is the most common problem I witness. The oil level should be maintained at the middle of the sight glass and no higher.
Why do you need a bearing isolator on a pump?
The edge of the lip seal contacted the rotating shaft, creating permanent damage. Bearing isolators are not just designed to keep the contamination out and away from the oil and the bearings; they are also designed to keep the oil in the bearing housing of the pump.
How are bearing isolators different from lip seals?
Bearing isolators/protectors are a marvelous improvement over the previously used devices—lip seals. To a lesser degree, interim devices on higher-energy pumps involved stationary and occasionally rotating labyrinths of both axial and radial designs. Modern bearing isolators consist of a non-contacting unitized rotor and stator combination.